Seabird-fishery interactions and bycatch at multiple gears in the Atlantic Iberian coast

2020 ◽  
pp. 105306 ◽  
Author(s):  
Joana G. Calado ◽  
Jaime A. Ramos ◽  
Ana Almeida ◽  
Nuno Oliveira ◽  
Vítor H. Paiva
Keyword(s):  
Fishery Interactions

Potential population and economic consequences of sublethal injuries in the spiny lobster fishery of the Florida Keys

2007 ◽  
Vol 58 (2) ◽  
pp. 166 ◽  
Author(s):  
D. M. Parsons ◽  
D. B. Eggleston
Keyword(s):  
Spiny Lobster ◽  
Florida Keys ◽  
Fishing Effort ◽  
Economic Consequences ◽  
Economic Losses ◽  
Growth Time ◽  
Potential Population ◽  
Lobster Fishery ◽  
Fishery Interactions ◽  
The Impact

Animals that interact with but are not retained by fishing gears may later die. The population and economic consequences of these sublethal fishery interactions are seldom known but may be significant. In the present study, a population model was used to quantify potential population and economic consequences of injuries that Caribbean spiny lobsters (Panulirus argus) sustain from fishing activities in the Florida Keys, USA. Injuries generated by the fishery are known to reduce growth and elevate mortality. Simulation modelling results indicated that injuries may reduce adult lobster abundance and associated landings by ≥50% in areas with high recreational fishing effort. When simulated injuries were ~20 times lower (representing areas with lower fishing effort), these injuries were only responsible for a 5 and 8% reduction in the adult lobster population and commercial landings respectively. Important parameters within the model (growth, time in stage and mortality of injured lobsters) were altered by ±10% to assess model sensitivity. Final results changed <10% (with the exception of one 15% change), suggesting that model output was relatively insensitive to variation in key parameters. When the impact of sublethal injuries was applied to the entire spiny lobster fishery in the Florida Keys, adult stock biomass and annual commercial landings were reduced by 900 and 160 t (US$1.6 million) respectively. These results suggest that sublethal fishery interactions can lead to high population and economic losses, and highlight the need to incorporate sublethal injuries into stock assessments and economic models.

scholarly journals Underwater observations of seal–fishery interactions and the effectiveness of an exclusion device in reducing bycatch in a midwater trawl fishery

2016 ◽  
Vol 73 (3) ◽  
pp. 436-444 ◽  
Author(s):  
Jeremy M. Lyle ◽  
Simon T. Willcox ◽  
Klaas Hartmann
Keyword(s):  
Mortality Rates ◽  
Video Monitoring ◽  
Underwater Video ◽  
Fishing Activity ◽  
Midwater Trawl ◽  
Trawl Fishery ◽  
Space And Time ◽  
Operational Factor ◽  
Fishery Interactions ◽  
Pelagic Fishery

Interactions between seals and midwater trawl operations in the Australian Small Pelagic Fishery are common and can be lethal. The nature of interactions and effectiveness of a seal exclusion device (SED) in mitigating lethal interactions was assessed using underwater video. Recent fishing activity and the phase of the trawl operation significantly influenced interaction rates; interactions increased with the amount of recent trawl activity and were highest while the trawl was being set. Most seals accessed the trawl via the net entrance and exited via an escape opening located at the base of the SED. The size of the escape opening was the only operational factor that influenced mortality rates — simply enlarging the escape hole reduced lethal interactions by 79%. However, since all deceased seals dropped out of the net before they were brought on board, they would have gone unobserved without video monitoring. Limiting the concentration of fishing activity in space and time and refinement of the SED design, in particular to address dropouts, is recommended if mortality rates are to be reduced.

scholarly journals Migrations, fishery interactions, and management units of sea bass (Dicentrarchus labrax) in Northwest Europe

2007 ◽  
Vol 64 (2) ◽  
pp. 332-345 ◽  
Author(s):  
M. G. Pawson ◽  
G. D. Pickett ◽  
J. Leballeur ◽  
M. Brown ◽  
M. Fritsch
Keyword(s):  
Dicentrarchus Labrax ◽  
Release Site ◽  
Sea Bass ◽  
European Sea Bass ◽  
Management Units ◽  
The North ◽  
Management Measures ◽  
Northwest Europe ◽  
Fishery Interactions ◽  
The Uk

Abstract Pawson, M. G., Pickett, G. D., Leballeur, J. Brown, M., and Fritsch, M. 2007. Migrations, fishery interactions, and management units of sea bass (Dicentrarchus labrax) in Northwest Europe. – ICES Journal of Marine Science, 64: 332–345. A total of 4959 sea bass was tagged between 2000 and 2005 around the coasts of England, Wales, southern Ireland, and the Channel Isles to investigate whether movement patterns documented in 1987 have changed and to estimate the level of competition for sea bass between inshore and offshore fisheries. Most (54%) of the recaptures of adult bass (fish >40 cm) tagged inshore and made between May and October were within 16 km of the release positions. From November on, an increasing proportion was recaptured at least 80 km south or southwest of tagging sites. Bass tagged on offshore spawning grounds in March and April showed reciprocal movement, 75% of recaptures between May and October being at least 80 km from the release site. These observations reaffirm the hypothesis that adult sea bass may move considerable distances to offshore winter spawning areas, but there was little evidence of the spawning migrations between the North Sea and the western Channel that were observed in the early 1980s. Just 3% of the recaptures of bass >36 cm tagged in UK inshore fisheries were reported from the offshore pairtrawl fishery, whereas half the recaptures of bass tagged in that fishery were made inshore along the UK coast. When weighted by the respective catches, this suggests that the effects of management measures implemented in the UK inshore fishery are largely restricted to that fishery. A proposal for stock units for assessment and management of NW European sea bass fisheries is presented.

scholarly journals Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin

2021 ◽  
Vol 8 ◽  
Author(s):  
Erin Ashe ◽  
Rob Williams ◽  
Alexandra Morton ◽  
Philip S. Hammond
Keyword(s):  
Killer Whale ◽  
Anthropogenic Impacts ◽  
Predatory Behavior ◽  
Orcinus Orca ◽  
Killer Whales ◽  
Mammal Conservation ◽  
White Side ◽  
Fishery Interactions ◽  
Serious Injury

Killer whale (Orcinus orca) populations specialize in both prey and prey acquisition tactics around the world and may be a primary evolutionary driver of the habits of small cetaceans. Entanglement in fishing gear is the most significant anthropogenic threat to the survival of cetaceans worldwide. Distinguishing between natural and human-caused sources of mortality and injury is a key task in marine mammal conservation and management. In British Columbia (BC), Canada, mammal-eating killer whales co-occur with Pacific white-sided dolphins (Lagenorhynchus obliquidens). Bycatch mortality rates are unknown here due to lack of systematic fisheries observer coverage. Drawing from more than three decades of first-hand observations of killer whale attacks on Pacific white-sided dolphins, we identify common themes with respect to predatory behavior of killer whales and anti-predatory responses of dolphins. With input from veterinary pathologists, we outline clues to distinguish killer whale rake marks from scars and wounds likely to be caused by fishery interactions. We examined photographs of 415 well-marked Pacific white-side dolphins for evidence of injuries and scars consistent with either killer whale attacks or fishery interactions. In this case study, healed scars from interactions with killer whale predators were ∼8× more common than scars from fishery interactions (3.9 vs. 0.5%), suggesting that predation is a much bigger threat to Pacific white-sided dolphins in the study area than anthropogenic impacts, or that dolphins are much less likely to survive a fishery interaction than a predation attempt. To advance our knowledge on poorly studied species, multiple lines of evidence will be needed.

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